Pen



FIG. 1 is a PERSPECTIVE view of a design for the pen;

FIG. 2 is a FRONT view thereof;

FIG. 3 is a BACK view thereof;

FIG. 4 is a TOP view of thereof;

FIG. 5 is a BOTTOM view thereof;

FIG. 6 is a SIDE view thereof; and,

FIG. 7 is a SIDE view thereof.

The Broken lines present in the figures are included for the purpose of illustrating portions of the article that form no part of the claimed design. 

CLAIM The ornamental design for a pen, as shown and described. 